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OBD2: All You Need to Know About The Federal Standard

If you’re someone who owns a car and often runs into car problems, you must have heard of OBD2 or OBD in case you have a model from early 90s.

In the modern world, our cell phones or laptops aren’t the only smart devices around anymore. With the incredible developments in technology and Artificial Intelligence, most of the things around us have some kind of computerized software to make our lives easier. One such thing is the OBD2 technology in our cars.

What is OBD2?

On-Board Diagnostic (OBD) is a system that helps you monitor and manage your car’s health and performance by interfacing with the car’s built-in computer system. This diagnostics system allows car owners or mechanics to check the status of various components within the car quickly. For instance, it can monitor the car’s transmission operation, air temperature, or even the ignition.

Cars from the 1980s and part of 1990s used an older version of this system, called OBD1. Modern cars use a more advanced version, known as OBDII or OBD2, which has more far-reaching implications for the automotive industry. So, if you’ve bought your car in the past 20 years, it’ll probably have OBD-II technology.

The OBD2 port is usually under the dashboard next to the steering column or at the bottom of the center console. You can use this port to connect your OBD2 scanner tool to your car’s diagnostic system.

Why Should You Use OBD2 Technology?

Even though OBD systems have been around since the 1980s, they weren’t the most accurate or reliable. The initial version, commonly known as OBD1, was not standardized either which caused even more problems for car owners. All this lead to the development of the much needed OBD2 technology.

The biggest problem with OBD1 was that different car manufacturers used different standards in their cars. This cause problem as you need a different scanner to interpret codes for each vehicle. This problem is resolved by OBD2 that follows international standard, so one universal OBD2 scanner is good enough for different cars.

OBD2 is also better in terms of accuracy and quality. From the smallest issues like a loose gas cap to much more serious concerns like engine misfires, OBD2 technology could diagnose it all.

How many times have you seen the Check Engine Light (CEL) turn on and wasted hours tinkering under the hood only to find out that it was just the exhaust pipe? Consequently, with OBD2 technology, you can not only detect but quickly troubleshoot your problems at the same time.

Furthermore, not only does OBD2 save time, but it also saves you a lot of money. Taking your car to the repair shop every other day for minor issues isn’t exactly cheap. But imagine how much money you could save if you could easily diagnose and fix your car yourself. However, you need an OBDII scanner to interpret the OBD2 codes.

Moreover, OBD2 technology involves a more sophisticated diagnostic system which not only alerts the driver if any car part breaks down, but it can monitor and warn the driver of deteriorating parts before they break down. As a result, OBD2 technology is essential in ensuring drivers’ safety while on the road.

OBD2 Diagnostic Connector

OBD2 Diagnostic Connector.
OBD Connector Shape.
Credit: commons.wikimedia.org

As mentioned earlier, the OBD2 port or diagnostic connector is found under the dashboard, and you can use it to connect the scanner. Even if it’s not under your dashboard, it is legally required to be within two to three feet from the driver and should be easily accessible. So, you might need to look around your dashboard and behind your ashtray to locate this connector.

The diagnostic connector, or the Data Link Connector (DLC), is a 16-pin port. The different pins in this connector will indicate which protocols the OBD2 scanner is communicating with. Although some pinouts vary from manufacturer to manufacturer, some pinouts follow similar standard throughout.

Consequently, this is why OBD2 scanners can read codes regardless of the protocol. Some of these standardized pinouts include Pin 4 and Pin 5 which are for the ground and Pin 16 which is for the battery voltage.

OBD2 Protocols

Although most diagnostic systems are standardized, there are some variations as different manufacturers have different preferences. These variations usually occur due to the different pinouts of the DLC. As a result, there are mainly five different types of pinouts which are the basic five communication protocols.

These five protocols are:

  1. SAE J1850 VPW (Variable Pulse Width): General Motors’ vehicles normally use this protocol, and you can identify it by the metallic contacts in Pins 2, 4, 5, 16.
  2. SAE J1850 PWM (Pulse Width Modulation): Vehicles from Ford use this protocol, and you can identify it by the metallic contacts in Pins 2, 4, 5, 10, 16.
  3. ISO 15765 CAN (Controller Area Network): This protocol is a part of either U.S. cars sold in 2008 onwards or some European cars sold in 2003 onwards. You can identify it by the metallic contacts in Pins 4, 5, 6, 14, 16.
  4. ISO 9141-2: Chrysler and many European and Asian cars use this protocol. You can identify this protocol by the metallic contacts in Pins 4, 5, 7, 15, 16.
  5. ISO 14230-4 KWP2000 (Keyword Protocol): Various European and Asian imports also use this protocol. Some of these vehicles include Subaru, Nissan, and Jeep.

OBD2 Codes/PIDs

OBD2 codes or Diagnostic Trouble Codes (DTC) indicate where the problem lies in your car. These codes follow a five-character format where the first character is a letter, and the rest four are numbers. Together, these characters indicate which component has a problem and the exact failure.

The first character could be the letter P for powertrain, B for body, C for chassis, or U for network. Similarly, the second character could be the number 0 for a government required code or the number 1 for a manufacturer unique code. The third character could be any number from 1 to 9 with each number referencing a system within the car.

The fourth and fifth characters could be any number from 00 to 99 and indicate the exact failure according to the system defined in the third character. Besides that, there are also OBD2 Parameter Identifications (PIDs) or Parameter IDs. Somewhat similar to the third character of the DTC, OBD2 PIDs are codes which you can use to obtain information about the car’s parameters you’re interested in.

All PIDs are not available with all protocols as manufacturers have unique PIDs within their separate protocols.

OBD2 Application

The OBD2 technology has wide-ranging applications, some of which we’ll briefly discuss below:

OBD2 Cable Scan Tools

OBD2 Scanner
OBD2 Cable Scan Tool.
Credit: commons.wikimedia.org

Scan tools are better versions of code readers. They have extensive features which enable them to analyze and troubleshoot the car’s problems.

Bluetooth OBD2 Scanners

These scanners can read and interpret OBD2 DTC and PIDs through a diagnostic app on a cellphone or tablet using Bluetooth signals.

PC-based OBD2 Software

To use this software, first you need to install it on your computer or laptop. Then, using a cable or other hardware, you can connect it to the DLC on your car for the usual OBD2 features.

Data Loggers

OBD2 data loggers can transfer the car system’s data and history into an SD card without using any app or Wi-Fi. Then, they can retrieve this data later for studying and analysis.

Emission Testing

Previously, tailpipe tests were used for emission testing. However, now many countries use OBD2 emission testing which is a far easier and cheaper method.

Driver’s Supplementary Vehicle Instrumentation

Some people install these are additional measures in their car for instant diagnostics, besides the regular OBD scanners.

10 OBD2 Service Modes

OBD2 systems include a list of ten diagnostic services, also known as the OBD2 service modes. They are as follows:

  • 01 – Shows live current data
  • 02 – Displays freeze frame data
  • 03 – Shows stored DTC
  • 04 – Clears DTC and values
  • 05 – Shows oxygen sensor monitoring test results
  • 06 – Displays test results of other system monitoring
  • 07 – Shows pending DTC
  • 08 – Allows control of on-board system
  • 09 – Requests vehicle information
  • 0A – Obtain permanent codes

Does Your Car Have OBD-II?

From 1996 onwards, it was a must for all light trucks and cars to be OBD-II technology compliant. So, if you bought a car any time after that, the chances are that your car does have OBD-II technology. Despite that, if you’re still not sure, there are two other ways to check.

Firstly, you can look around for the 16-pin DLC somewhere around your steering column. Secondly, you can check under your hood for a note or sticker stating that your car is OBD-II compliant. Either of the two you find will confirm that your car does have OBD-II technology.

OBD2 simple introduction.
Credit: youtube.com


Simply put, OBD2 is an upgrade of OBD1, a system that was introduced to check malfunctions in our vehicles in the early 90s. OBD2 technology in modern car models is more intelligent. It allows mechanics and even car owners to diagnose problems with their car if they have an OBD scanner. This makes not only things easier for mechanics, but also allows you to understand the problem better.

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